% perl -d -e '$#{@1}'
Default die handler restored.

Loading DB routines from perl5db.pl version 1.07
Editor support available.

Enter h or `h h' for help, or `man perldebug' for more help.

main::(-e:1):	$#{@1}
  DB<1> c
Bizarre copy of ARRAY in leave at -e line 1.
Debugged program terminated.